(a) Field of the Invention
The present invention relates to a method and apparatus for protection switching in an optical transport network, and more particularly, to a method for protection switching in an optical transport network supporting a flexible optical channel data unit function.
(b) Description of the Related Art
An optical transport network supports a wide bandwidth, high reliability, a well-developed protection switching function, and an operation, administration, and maintenance (OAM) technique. Thus, research into transmitting packet data through an optical transport network, which is currently explosively increasing, is actively ongoing.
In order to effectively receive packet client signals through an optical transport network, ITU-T, an international standardization organization, defined a flexible optical channel data unit (ODUflex) and defined the same so as to be multiplexed through a generic mapping procedure (GMP) in a higher hierarchy ODUk (k=2, 3, 4). The use of the ODUflex technology is advantageous in that bandwidth can be managed for each ODUflex, and bandwidth can be increased or decreased. This allows for effectively receiving packet data having burst characteristics. However, the related art optical transport network technology, which simply multiplexes a signal input from a client interface to a time-division multiplexing (TDM) signal having a higher transfer rate and transmits the same, provides only a protection switching function of a wavelength unit, it is disadvantageous in that a bandwidth set for each ODUflex cannot be effectively operated. Thus, in order to transparently receive Ethernet data and enhance network efficiency, a protection switching function for each optical channel, i.e., for each ODUflex, rather than the current protection switching function of a wavelength unit, in an optical transport network is required.